It's a stereo-field manipulation/pitch adjuster/phase-fixer, and more, made to look like a vacuum-tube era studio device. It's sort of a console-strip in a different form-factor.
XTrim works very well and retains all of its skeumorphism as it does. Rotate the knobs and the specular highlights (bright spots) stay in place as the knob rotates very, very precisely, meaning hundreds of images were made for each knob. Despite the incredible skeumorphism it provides extremely precise adjustments.
Narrowing and Panning
One piece of its functionality that I use is the stereo field narrowing and panning. Many physical and virtual synthesizers produce exaggerated stereo (which sounds good in the music store, or in a demo) which becomes difficult in a mix. Imagine serveral different instruments, each with its own idea of the stereo field. You can't meaningfully move them to toward the left or right. You can merge to mono, and then pan, but the phase shifts that create the stereo field then become phase cancelations that greatly alter the tone and behavior. What you need, and what this tool does, is to narrow the stereo field of each instrument to taste and then be able to move the instrument to where you want it. After I saw this thing, I had to have it, just looking at the images, but it is extremely useful just for this one of its features. This is just one (two, really) of its features. I could implement these features now that I understand the idea, using serveral different plugins with different user interfaces and different ways of storing settings. I certainly won't do that when Sknote offers this lovely piece of work for $19.99 US. If I want to, I can use one on each instrument in a mix.
Copy Protection that doesn't leave you stranded
The copy protection is unintrusive and allows you to make backups.
One possible improvement
What do I think could be improved? The labels are deliberately fairly low contrast against the background. The graduations around the knobs are fine, but at the standard fixed size of the GUI, the labels are hard to read, and made harder by the acronyms. I think the labels need to be a bit brighter. The acronyms are standard ones and should be kept for space reasons as on the original devices.